The present disclosure is directed to a fuel supply system and, more particularly, to a fuel supply system for an internal combustion engine.
An internal combustion engine operates when a fuel, such as, for example, diesel, gasoline, or natural gas, is combusted in a series of combustion chambers. The internal combustion engine typically includes a fuel supply system that delivers the fuel to each of the combustion chambers. A fuel supply system for an internal combustion engine typically include a series of fuel injectors that inject a certain quantity of fuel into each combustion chamber. The injected fuel mixes with intake air in the combustion chamber to form a combustible mixture.
The combustible mixture is then ignited through, for example, a spark or by compression. The subsequent combustion of the fuel and air mixture drives a piston associated with the combustion chamber through a reciprocal motion in a cylinder. The driving motion of the piston is translated into a rotation of a crankshaft, which may be used, for example, to operate a power generator or to power a vehicle.
The performance of the engine may be improved by optimizing the combustion conditions of the fuel and air mixture in the combustion chamber. For example, improving the mixing characteristics, or distribution, of the fuel and air mixture may improve the combustion process. A combustible mixture with an even distribution of fuel and air may combust more completely than a mixture with an uneven distribution of fuel and air. A more complete combustion may result in an increase in the overall performance of the engine in terms of either improved efficiency or reduced emission generation.
One method of improving the mixing characteristics of the fuel and air mixture involves increasing the pressure of the fuel before the fuel is injected to mix with the intake air. When the pressurized fuel is released into the combustion chamber, the pressure of the fuel causes the fuel to disperse into the intake air. This dispersion aids in evenly distributing the fuel within the intake air.
The pressure of the fuel may be increased through any of several different methods. For example, as shown in U.S. Pat. No. 6,102,004 to Cowden et al., a fuel injection system may include a pair of pumps that act to increase the pressure of the fuel. A first pump, or transfer pump, may be adapted to transfer a flow of fuel from a fuel tank through a series of filters to a second pump. The second pump, or high pressure pump, may be adapted to increase the pressure of the flow of fuel to an injection pressure.
The mixing characteristics of the fuel and air mixture may be optimized by maintaining the actual injection pressure of the fuel at or near a desired injection pressure. Any deviations in the actual injection pressure from the desired injection pressure may detract from the mixing characteristics of the air and fuel and, thus, detract from the overall engine performance. Because the high pressure pump typically applies a relatively constant amount of work to the flow of the fuel, the injection pressure at the outlet of the pump will depend, at least in part, upon the pressure of the fuel at the inlet of the high pressure pump.
The pressure of the fuel at the inlet of the high pressure pump may depend on several factors. For example, the pressure of the fuel may depend upon the operation of the first pump, the condition of the filters, and the fuel demands of the engine. A change in any of these factors may cause a change in the pressure of the fuel at the inlet of the high pressure pump and a corresponding change in the overall performance of the engine.
The fuel supply system of the present disclosure solves one or more of the problems set forth above.
In one aspect, the present disclosure is directed to a fuel supply system. The system includes a first pump adapted to generate a flow of fuel and a second pump in fluid connection with the first pump and adapted to increase the flow of fuel to a predetermined pressure. A fuel filter is disposed between the first pump and the second pump. A sensing line is adapted to provide an indication of the pressure of the flow of fuel between the filter and the second pump. A pressure regulator is adapted to receive the indication of the pressure of the flow of fuel and to control the flow of fuel delivered to the fuel filter based on the indication of the pressure.
In another aspect, the present disclosure is directed to a method of supplying fuel to an internal combustion engine. A flow of fuel is provided with a first pump. The flow of fuel is filtered with a filter disposed in fluid connection with the first pump. The pressure of the flow of fuel is increased to a predetermined pressure with a second pump. The flow of fuel between the first pump and the filter is regulated based on a sensed pressure of the flow of fuel between the filter and the second pump.